Inoculation and transfer loop and sterilizer

ABSTRACT

An improved sterilizer is provided for inoculation and transfer loops, needles, and other instruments formed of metals of high electrical resistance. The sterilizer includes a member having a V-shaped groove therein adapted to receive and support an instrument. A pair of electrodes are positioned on opposite sides of the groove so that an instrument resting in the groove completes the electrical circuit between the electrodes. The sterilizer also includes a removable hood having a single opening at one end disposed above the electrodes. An improved instrument designed to insure proper contact with the sterilizer electrodes is also provided. The instrument includes a loop and a pair of transverse tabs which extend outwardly from extensions of the loop for a distance greater than that between the electrodes.

D United States Patent 1 1 1 1 3,742,187

Folus 1 June 26, 1973 [54] INOCULATION AND TRANSFER LOOP AND 3,436,1714/1969 Weichselbaum et al..... 219/242 UX STERILIZER 2,051,759 8/1936Turpin et al. 219/242 X 2,310,844 2/1943 Draeger 219/233 X InventonStanford Folus, Randallstown, 3,168,640 2/1965 Rosenthal 219/242Baltimore, Md.

[73] Assignee: Becton, Dickinson & Company, East Primary Examiner-ABal'tis Ruth f d, N Attorney-Kane, Dalsimer, Kane, Sullivan & Kurucz[22] Filed: Oct. 22, 1970 [57] ABSTRACT [21] Appl. No.: 83,268

An 1mproved stenhzer is provided for inoculation and transfer loops,needles, and other instruments formed Cl 123/301 1, of metals of highelectrical resistance. The sterilizer in- 195/120, 195/127, 219/233,219/2 219/533 cludes a member having a V-shaped groove therein lllt- ClH0511 A611 1 C1213 1/02 adapted to receive and support an instrument. Apair of Search of electrodes are positioned on oppo ite ide f the128/3031, groove so that an instrument resting in the groove com- 1 533;30/140 pletes the electrical circuit between the electrodes. The

sterilizer also includes a removable hood having a sin- References Citedgle opening at one end disposed above the electrodes. UNITED STATESPATENTS An improved instrument designed to insure proper 2,511,1926/1950 Barroso 219 240 Contact with the Sterilizer electrodes is alsoProvided- 77 953 Oates 219 247 The instrument includes a loop and a pairof transverse 2,134,378 10/1938 Rosenthal.. 219/479 tabs which extendoutwardly from extensions of the 2,7 4,650 55 e er t 219/247 loop for adistance greater than that between the elec- 1,679,756 8/1928 Allen219/247 trodes, 2,421,125 5/1947 Krebs 30/140 2,101,913 12/1937 Meyer219/233 X 2 Claims, 4 Drawing Figures LIMITlNG CURRENT CIRCUITRYPAIENIEDJUNZB I973 3,742,187

sum 1 or 2 ii q \CURRENT LIMITING FIG. I. CIRCUITRY STANFORD G. FOLUSINVENTOR BY aka (4% fin? ATTQZg PATENTEDJUHZS ms 3.742.187

sum 2 or 2 STANFORD G. F OLUS INVENTOR z ("CQM4A/Q'%TORNEW INOCULATIONAND TRANSFER LOOP AND STERILIZER BACKGROUND OF THE INVENTION The presentinvention relates to a sterilizer particularly adapted for use insterilizing inoculation arid transfer needles, loops, or other similarinstruments by igniting microorganisms which may collect on theinstruments. Such instruments are commonly used in microbiologylaboratories for transferring microorganisms from one vessel orcontainer to another, such as from a culture to a nutrient medium. Theinstruments generally are formed in the shape of an elongated wire rodor needle having a loop at one end. The diameter of the loop and wiregauge may be calibrated to precisely control the amount ofmicroorganisms transferred. A suitable handle or wand may be attached tothe nonlooped end of the instrument to facilitate handling.

Heretofore, it has been common to clean and sterilize such instrumentsby exposing the microorganism carrying loop to the open flame of aBunsen burner. This procedure is undersirable for several reasons, themost important of which recognizes the dangers inherent in having anexposed flame in a work area and the danger of spattering when ignitionoccurs. This latter danger is of particular importance where pathogenicmicroorganisms are being transferred.

In U. S. Pat. Nos. 2,134,378 and 3,436,171 two electrical devices forsterilizing inoculation instruments are disclosed. Both these devices,however, have several drawbacks, the most important being that theyeither require that the sterilizer be constantly on or that thetechnician periodically turn the sterilizer on prior to each use. Also,these instruments require that the technician shift the instrument inhis hand in order to utilize the sterilizer. This type of maneuver istiring for the technician and further, is dangerous since it increasesthe possibility of contamination during use.

In view of the above, it is the principal object of the presentinvention to provide a device for use in the sterilization ofinstruments formed of electrically conductive materials and particularlyinoculation and transfer loops and needles which is automaticallyactivated when an instrument is placed in position for sterilization.Another object is to provide such a device which overcomes thedisadvantages of the prior art devices and which is relatively simple inconstruction, formed of a minimum number of parts and may be producedand marketed economically.

SUMMARY OF THE INVENTION The above and other beneficial objects andadvantages are attained in accordance with the present invention byproviding a device for use in the sterilization of instruments formed ofelectrically conductive material comprising a support structuresupporting thereon first and second electrodes. The electrodes are fixedto the support structure and disposed at an acute angle with respect toeach other so as to define a V-shaped groove between them. The supportstructure and electrodes are contained within a hood having a singleopening at one end and the hood inclines downwardly from the open end.

In use, an instrument is inserted into the hood through the open end andallowed to rest on the electrodes. The instrument thus serves tocomplete the electrical circuit between the electrodes so that thecurrent flowing through the instrument serves to heat it. When theinstrument is removed from the electrodes, the circuit is automaticallyopened and the sterilizer is thus turned off without requiring anyadditional step to be performed by the technician.

An improved inoculation and transfer instrument particularly adapted foruse with the present sterilizing device is also provided. The instrumentcomprises a length of wire of high electrical resistance material, suchas Nichrome, having a loop formed in the approximate midsection. Bothends of the wire extend longitudinally from opposite sides of the loopin the same direction and terminate in contact tabs which extendtransverse to the longitudinal axis of the instrument in oppositedirections. The tabs are designed so that the distance between the freetip of each tab is greater than the distance between the two electrodesof the sterilizing device.

The instrument is used with a wand or handle formed of an insulativematerial such as plastic. The wand comprises an elongated member havinga pair of opposed slits extending longitudinally from one end which extend radially inwardly from opposed surfaces. The cross sectionaldimension of the wand measured be tween the slits is less than thedistance from tip to tip of the instrument tabs so that when theinstrument is placed in the .wand, each tab extends radially outwardlybeyond the outer surface of the wand. Since the dimension between thefree tips of the tabs is greater than the distance between theelectrodes of the sterilizing device, when the instrument is positionedin the .V groove each tab contacts one of the electrodes. The instrumentwand and sterilizer are also provided with complemen- 'tary stopsdesigned to engage each other when the instrument tabs are aligned withthe electrodes to insure proper contact.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. 1 is a partially cutaway side elevational view of a sterilizingdevice in accordance with the present invention;

FIG. 2 is a fragmentary perspective view of the electrode configurationof the sterilizing device;

FIG. 3 is an exploded perspective view of an inoculation loopparticularly adapted for use with the present device; and

FIG. 4 is an alternate embodiment of the loop of FIG. 3.

DETAILED DESCRIPTION OF THE PREFFERED EMBODIMENT Reference is now madeto the drawings wherein the present invention is illustrated in detailand wherein similar components bear the same reference numeralthroughout the several views.

In FIG. 1, a sterilizing device 10, in accordance with the presentinvention is illustrated. The sterilizing device includes a base 12 andhood 14. The base contains a transformer 16 and suitable currentlimiting circuitry 18 which is controlled by a variable switch 20mounted to the front of the unit. Such circuitry is well-known topersons familiar with the art and may be formed of conventional, readilyavailable components. The transformer 16 has a line cord 17 connected toits input terminals to permit connection to a power source through aconventional outlet. A block of insulative material 22 is mounted to thetop of the base close to the front of the unit. A V-shaped groove 24extends downwardly into block 22 from the top surface at the approximatemidpoint. The groove 24 is defined by surfaces 26 and 28 which aredisposed at an acute angle with respect to one another.

An electrode in the form of a contact terminal 30 is secured to surface24 and a similar terminal is secured to surface 28. Each of theterminals'is connected to one of the output leads of the currentlimiting circuitry H8. The terminals comprise strips of highlyconductive material, such as copper, and cover the major portion oftheir associated insulator block surfaces.

The entire top of the base 12 is designed to be covered by a removablehood 14. The hood, is designed to seat snuggly on top of the baseforming an enclosure about the base. The hood should be formed of anautoclavable material such as Lexan or any other suitable material,preferably a transparent material. One end of the hood defines a wideopening providing access to the enclosure. As will be noted from FIG. l,the base and hood incline downwardly from the open end 32 to a closedend 34. It may also be noted that the electrodes are positioned proximalthe open end 32. It has been found that if the hood slopes downwardly atan angle of about 35, the sterilizer may be used by a technician withoutrequiring that he shift the position of the instrument in his hand fromthe normal transferring position. This angle also insures that allaerosols released during the sterilization process will be trappedwithin the hood.

In FIG. 3 an inoculation loop which may readily be sterilized with thesterilizing device it) is illustrated. The instrument is designed with abend configuration which provides for a precise loop to pick up thedesired aliquots and yet retain the proper current path for totalsterilization. To this end, the instrument 420 comprises a work zone inthe form of loop 42 formed in a wire of high resistance material such asnichrome wire. The loop 42 is in the approximate center of the wire. Apair of parallel legs 44 and 46 extend rearwardly from the ends of theloop. The legs each terminate in a contact tab, 48 and 50 respectively,which is formed of a highly conductive material, such as copper. Thetabs extend toward free tips 52 and 54 generally transverse to thelongitudinal axis of the instrument and the spacing between the freetips 52 and 54 is somewhat greater than the distance between thesterilizer electrodes.

A wand or handle 56 is provided for association with the loop. Thehandle comprises an elongated, generally cylindrical member having aforward end MI and rearward end 611. A pair of opposed radial slits gextend rearwardly from the forward end 60. Each of the slits alsoextends radially inwardly from the outer periphery of the wand for adistance less than the transverse length of an associate tab (50 or 52)of the instrument so that the tips 52 and 54 of the tabs extend beyondthe outer surface of the wand. A longitudinally shiftable ferrule 55 isprovided about the handle 56. The ferrule, when shifted forwardlyisdesigned to compress locking humps 57 molded onto the handle to lockthe instrument 40 in position. Accordingly, when the ferrule 55 is in arearward position as depicted in FIG. 3, the slits 58 are sufficientlyshifted to receive the opposed tabs. However, when the ferrule isshifted forwardly, it

serves to squeeze the slits together by compressing the humps 57 therebylocking the instrument in position.

The instrument and handle may be separable as shown in FIG. 3, or,alternately they may be permanently joined such as by potting the slitswith a suitable potting compound as shown in FIG. 4. In either event,the free ends 52 and 54 of the tabs extend beyond the outer surface ofthe wand. The wand should be formed of an insulating material and be ofa diameter which renders it comfortable in the hand of the user.

In use, current is supplied to the present sterilizer ill by pluggingcord ll'l into a suitable outlet. No current will flow since thesterilizer circuit is interrupted between the electrodes. To sterilizethe instrument 4t) utilizing the device 10, all that is necessary is forthe user to insert the device within the wide mouth opening 32 of thehood and allow the exposed tab tips 52 and 54 to rest on contacts 30.This will automatically close the circuit through the instrument and ina short'time cause the wire to glow cherry red and burn off any matterdisposed on, the wire. It should be noted that the sterilizer mayaccommodate instruments of various lengths since electrical contactoccurs at the tabs. To facilitate the registry of the tabs 52'and $4with the contact, a stop 62 may be provided at the forward end of theinsulating block 22. This stop is suitably positioned and dimensioned toengage the forward end 60 of the wand and prevent further insertion ofthe wand into the housing when the tabs are aligned with the contacts.The V- shaped groove and the disposition of the contacts on the surfacesdefining the groove insures a good electrical contact being made eachtime the device is used. The current applied to the instrument andhence, the rate at which sterilization occurs may be regulated bysuitably adjusting knob 20 so that rapid sterilization without burningof the loop may be obtained for a variety of instruments of varyingdiameter.

Having thus described the invention, I claim:

1. In combination: an inoculation and transfer loop formed of a highresistance, electrically conductive material; a work zone on said loop;first and second leg portions on said loop spaced apart from each otherand disposed on opposite sides of said work zone and electricallyconnected thereto; and a sterilizing device for said loop, saidsterilizing device including a support structure including a top surfaceand having a V- shaped groove extending downwardly from said topsurface, said groove being defined by a pair of surfaces disposed at anacute angle with respect to one another; a first electrode affixed toone surface of said groove insulated therefrom, a second electrodeaffixed to the other surface of said groove and insulated therefrom,said electrodes being spaced apart from one another; means forinterconnecting said first and second electrodes to the output terminalsof .a power supply; and a hood enclosing said entire support structureincluding said electrodes, said hood including surfaces at one enddefining an opening providing the only access opening to saidelectrodes, said electrodes being disposed proximal to said hood openingand said hood sloping downwardly from said opening to an opposite end,said electrodes being spaced apart from each other a distance somewhatless than the distance between said loop leg portions whereby each ofsaid leg portions may engage one of said electrodes to close the circuitbetween said electrodes through said loop.

2. The invention in accordance with claim 1 further legs, each tabextending away from the opposite leg, comprising a tab formed ofelectrically conductive masaid tabs adapted to comprise the points ofengagement terial affixed and electrically connected to each leg andbetween said loop leg portions and the electrodes. extending transverseto the longitudinal axis of said

1. In combination: an inoculation and transfer loop formed of a highresistance, electrically conductive material; a work zone on said loop;first and second leg portions on said loop spaced apart from each otherand disposed on opposite sides of said work zone and electricallyconnected thereto; and a sterilizing device for said loop, saidsterilizing device including a support structure including a top surfaceand having a V-shaped groove extending downwardly from said top surface,said groove being defined by a pair of surfaces disposed at an acuteangle with respect to one another; a first electrode affixed to onesurface of said groove insulated therefrom, a second electrode affixedto the other surface of said groove and insulated therefrom, saidelectrodes being spaced apart from one another; means forinterconnecting said first and second electrodes to the output terminalsof a power supply; and a hood enclosing said entire support structureincluding said electrodes, said hood including surfaces at one enddefining an opening providing the only access opening to saidelectrodes, said electrodes being disposed proximal to said hood openingand said hood sloping downwardly from said opening to an opposite end,said electrodes being spaced apart from each other a distance somewhatless than the distance between said loop leg portions whereby each ofsaid leg portions may engage one of said electrodes to close the circuitbetween said electrodes through said loop.
 2. The invention inaccordance with claim 1 further comprising a tab formed of electricallyconductive material affixed and electrically connected to each leg andextending transverse to the longitudinal axis of said legs, each tabextending away from the opposite leg, said tabs adapted to comprise thepoints of engagement between said loop leg portions and the electrodes.